This only changes behaviour for masters, as developers are already prevented from updating/deleting tags without the Protected Tags feature

Fixes ProtectedBranches#create flash errors bug due to
typo in 'flash[:alert] = @protected_branches.errors'

This memorized array appears to originally come from https://gitlab.com/gitlab-org/gitlab-ee/commit/19c2c90ccac86a21eb4266b9a5972162f917f692 which has a commit message of ‘fix warnings’. Without any comments on the original pull request I think we can safely get rid of it unless warnings re-appear.

Makes it clear this is only used in dropdowns, instead of cluttering up Project class. Since we only care about branch names, it is also possible to refactor out a lot of the set/reject logic.

A benchmark on Array/Set subtraction favoured using Arrays. This was with 5000 ‘branches’ and 2000 ‘protections’ to ensure a similar comparison to the commit which introduced using Set for intersection.

Comparison:
   array subtraction:      485.8 i/s
     set subtraction:      128.7 i/s - 3.78x slower

Uncommented protected tags feature specs copied from protected branches

Fixed timestamps on protected_tags

Should provide basic CRUD backend for frontend to work from. Doesn’t include frontend, API, or the internal API used from gitlab-shell

Added schema.rb for protected tags